Dual diaphragm three-position actuator

ABSTRACT

A three-position vacuum actuator having a housing including two diaphragms clamped between parts of the housing and a fluid communicating spacer ring located between the outer edges of the diaphragms. Fluid communication passages lead into all three chambers formed by the casing and the two diaphragms. Springs are in each of two operating chambers, one spring biasing the diaphragms apart and another spring biasing one diaphragm toward the other. An operator rod extends through the casing wall and is secured to one diaphragm. A collapsible link unit connects the two diaphragms so they can move toward each other yet the separated condition of the two diaphragms is limited. The actuator in assembly with a valve will operate the valve through three positions.

United States Patent Jamestown, N.Y.

[21 1 Appl. No. [22] Filed [45} Patented 73] Assignee [54] DUAL DIAPHRAGM THREE-POSITION ACTUATOR 39 Claims, 28 Drawing Figs.

[52] U.S. Cl 92/48, 92/97, 92/98 [51] Int. Cl F01b 19/00 [50] Field of Search 92/48, 49, 103, 97, 64, 98; 74/581, 582,585; 63/4 [56] References Cited UNITED STATES PATENTS 2,577,967 12/1951 Hughes 92/97 X 1,847,901 3/1932 Roy 63/4 2,095,547 10/1937 Girouard 63/4 X 2,840,339 6/1958 Price 92/103 X 2,867,241 1/1959 Fitz Harris. 92/103 X 2,192,117 2/1940 Wile 92/48 X 2,680,375 6/1954 Schaus 92/48 X 2,902,008 9/1959 Price et al 91/49 2,989,035 6/1961 Stelzer 92/48 X 3,048,361 8/1962 Francis... 92/49 X 3,156,161 11/1964 Forsman etal... 92/140X 3,303,747 2/1967 DeMay et a1. 92/98 3,375,838 2/1968 Cheek et a1.... 92/97 UX 3,385,174 5/1968 Crosland 92/100 3,431,824 3/1969 Damm.... 92/140 3,433,132 3/1969 James 92/98 Primary ExaminerMartin P. Schwadron Assistant Examiner- Leslie J. Payne Att0rney-Strauch, Nolan, Neale, Nies & Kurz ABSTRACT: A three-position vacuum actuator having a housing including two diaphragms clamped between parts of the housing and a fluid communicating spacer ring located between the outer edges of the diaphragms. Fluid communication passages lead into all three chambers formed by the casing and the two diaphragms. Springs are in each of two operating chambers, one spring biasing the diaphragms apart and another spring biasing one diaphragm toward the other. An operator rod extends through the casing wall and is secured to one diaphragm. A collapsible link unit connects the two diaphragms so they can move toward each other yet the separated condition of the two diaphragms is limited. The actuator in assembly with a valve will operate the valve through three positions.

PATENTEUHBT 19 Ian SHEET 18F 3 INVENTOR Jesse A. Johnson mwwwzw ATTORNEYS PATENTEBum 19 ml 3,613 513 SHEET 2 OF 3 INVENTOR Jesse R Johnson ATTORNEYS PATENTEUnm 19 |97l 3,613,513

' SHEET 3 BF 3 FIG 23 INVENTOR Jesse E. Johnson ATTORNEYS DUAL DIAPHRAGM THREE-POSITION ACTUATOR BACKGROUND OF THE INVENTION This invention relates to multiposition expansible chamber actuators and more particularly to a three position vacuum actuator useful for control operations such as shifting valves, fresh air dampers and the like on automotive equipment or other apparatus.

Vacuum motors or differential pressure expansible chambers motors are well known to those skilled in the art and it has been previously proposed to utilize multiposition vacuum actuators particularly in the automotive field. For the most part, previously known multiposition vacuum actuators have not received widespread acceptance because of their complex construction both as to piping, internal valving, requisite external valving and as to a actual physical construction, e.g., overall length, needed to accommodate components such as housing extensions which were used to obtain three-position actuation.

Accordingly, one of the primary objects of the present invention resides in the provision of a novel three-position vacuum actuator having a minimum number of parts and being economical to manufacture.

Another object resides in the provision of a novel vacuum actuator having a housing enclosing two diaphragms, the space between which can be connected to a source of vacuum through an edge opening in the housing and one of the spaces defined between one of the diaphragms and the housing also having provision for connection with a source of vacuum.

Another object of the present invention resides in the provision of a novel multiposition vacuum actuator which has two diaphragms, one of which is connected to an operating link, and including a lost motion collapsing link assembly connecting between the two diaphragms.

Still another object of this invention resides in the provision of a multiposition vacuum actuator including two diaphragms, the peripheries of which are spaced apart and by a fluid communication'spacer ring which by coaction between two parts of the actuator housing also sealingly clamps the diaphragms in assembly. Further objects reside in providing the fluid communicating spacer ring made from molded plastic material or glass fiber impregnated plastic material or made from metal.

Still another object resides in the provision of an efficient three position actuator which eliminates need for moving seal fittings and maintains the overall length dimensions to a minimum by avoiding housing extensions.

A still further object resides in the provision of a dual diaphragm three position vacuum actuator in which the operator rod and diaphragms are interconnected in such a manner as to avoid chatter and inaccurate or sloppy positioning at the intennediate actuator position. In conjunction herewith a further object resides in the provision of an interconnected relationship between both diaphragms and the operator rod permitting as much as deflection from a straight push-pull path without effecting the efficiency of operation.

A still further object resides in the provision of a novel compact, dual diaphragm three-position actuator having positive connections between an actuator link and the diaphragms, in combination with a control unit enabling three-posiiton con trol of the unit. In conjunction with this object of a further object resides in providing the actuator with a deflectable operator link connected to and in combination with a rotary plug valve controllable to an intermediate flow position between its off and open condition.

Other objects reside in provision of a novel three-position dual diaphragm actuator requires no external projection to accommodate the three-position feature; the diaphragms are interconnected by a collapsible interconnecting link assembly which can collapse into minimum space normally existing between the collapsed diaphragms, the collapsible link assembly will hold the two diaphragms at a fixed maximum distance apart; the collapsible link assembly depending upon various operating conditions canbe made from metal or nonmetallic matriahthe specific connectionof the collapsible link assembly to the diaphragm supports aids in accomplishing .the minimum space requirements; ribs molded on at least the front diaphragm enables the double diaphragm feature to operate with reliability, and an annular step or recess in the spacer ring is provided and cooperates with the diaphragm having the aforenoted ribs to further assure reliable operation of the double diaphragm feature.

Further novel features and other objects of this invention will become apparent from the following detained description, discussion and the appended claims taken in conjunction with the accompanying drawings showing preferred structures and alternative embodiments, in which:

FIG. I is a sectional view of a preferred embodiment of an actuator made in accordance with the present invention, illustrating the extended position of the actuator operating rod when neither of the operating chambers have a vacuum source connected thereto;

FIG. 2 is a sectional view similar to FIG. I showing the operator rod and the two diaphragms in shifted position when the rear chamber is subjected to vacuum;

FIG. 3 is a sectional view similar to FIGS. 1 ans 2 showing the position of the operator rod and diaphragms when vacuum is applied to the operating chambers (middle and rear) and the link assembly between diaphragms is in a fully collapsed condition;

FIG. 4 is a side elevation view showing a three position actuator assembled in combination with a valve controlled thereby an accord with the present invention;

FIG. 5 is a partial front elevation view of the assembly shown in FIG. 4 illustrates the connection between the actuator operator rod and the valve plug rotating lever;

FIGS. 6 and 7 are enlarged side and front views, respectively, of the preferred metal embodiment of the collapsible link assembly;

FIG. 8 is an enlarged detail section through a portion of the actuator housing and spacer ring to illustrate details of the cooperating structure FIG. 9 is a partially sectioned side view of one of the diaphragms;

FIGS. 10 and 11 are enlarged plan and side views, respectively, of one embodiment of the diaphragm support discs which include collapsible link anchoring parts;

FIGS. 12-28, which illustrate various embodiments of collapsible link units as well as several suitable modifications of other actuator components, are generally described as follows:

FIGS. 12 through 14 illustrate use of a steel spacer ring and a molded nonmetallic, X-shaped collapsible link unit;

FIGS. 15 and 16 are detail views which illustrate a double loop collapsible link unit constructed with molded, diamondshaped nonmetallic units;

FIGS. 17 and I8 are detail views which illustrate a single wide band collapsible link unit made form nonmetallic material;

FIGS. 19 and 20 are detail which illustrate use of a nonmetallic O-ring as the collapsible link unit between two diaphragms;

FIGS. 21 and 11 are enlarged O-n'ng sections illustrating fabric reinforced O-rings which can be used as the collapsible link unit shown in FIG. 20;

FIG. 23 depicts a thin flat plastic ring which can be used in lieu of the Oring unit in FIG. 20;

FIGS. 24-27 are detailed views illustrating metallic torsion spring embodiments of a collapsible link assembly, FIGS. 26 and 27 being enlarged plan views or the two different torsion springs which are used; and

FIG. 28 is a perspective view of an alternative embodiment of the collapsible link diaphragm anchor disc which can be used in lieu of the diaphragm support disc shown in FIGS. l0 and ll.

With reference to FIGS. 4 and 5, a three-position vacuum actuator or motor 30 is illustrated in assembly with a rotary plug valve 32, an example of which is depicted in US. Pat. No. 2,973,l8l. The combined actuator-valve assembly shown in FIG. 4 can be used in automotive heating systems and cooling systems, in which, for example, two different rates of flow of fluid through the valve as well as a valve shutoff condition are desired. The actuator could be used to operate something other than the depicted valve for example, and again referring to the automotive field, it may be used for setting the positions of heater duct dampers and outlet control doors. Suitable sources of vacuum, e.g., 10 inches to inches Hg., are normally available in automotive installations and the present actuator can utilize such available vacuum pressures.

In the assembly shown in FIG. 4, both the actuator 30 and the valve 32 are mounted on a sheet metal support bracket 34, the actuator being secured by bent over lugs 36 which are part of the actuator housing, as will be more fully described and the valve body 38 being similarly secured by bent lugs to a right angled platform portion 40 of the same bracket. In lieu of the lugs 36, threaded studs 37 (see FIG. 12) welded to the actuator housing can provide the means for fastening the actuator to a support structure. The actuator in FIGS. 4 and 5 illustrated with an L-shaped round operator rod 42 its terminal end 44 being bent to provide a portion which fits into an aperture in and serves to operatively connect with the valve plug rotating lever 46. The valve plug stem 48 is secured to its operating level 46 be staking. When the actuator operator rod 42 is in the extended condition, the valve is in its open condition with lever end 50 abutted against limit lug 52. When actuator 30 is moved to its limit position, rod 42 is retracted causing valve operating lever 46 to swing and rotate the valve plug to a valve full closed condition in which the other end 54 of lever 46 will abut a second limit lug 56. The intermediate position of the three-position actuator locates the valve lever 46, with the plug, intermediate the two limit conditions.

Upon reviewing FIG. 5, it will be understood that the actuator operator rod 42 must tilt, relative to its illustrative alignment with the in-line axis of the actuator housing, as it is retracted and the valve lever 46 swings in an are between its limit conditions. This feature of the actuator operator rod tilting or deviating from a straight line path is accommodated by the internal construction of the actuator and is now noted inasmuch as the exemplary actuator-valve assembly discloses one manner in which this ability, not normally present in three-position actuators, can be utilized while avoiding the need for additional articulation links which are expensive and require added space.

Instead of making the actuator operator rod from round rod stock as shown in FIGS. 4, 5 and 12, it can be and is preferably made from flat bar stock in the manner of rod 104 shown in FIG. 1, 2 and 3, the details of which will now be described.

Shown in FIGS. 1, and 2 and 3 is a preferred construction of an actuator 60 which is functionally the same as actuator 30. Actuator 60 is a three position, dual diaphragm, spring return vacuum actuator, in which the two diaphragms 62 and 64 are contained within the two part casing or housing 66 consisting of a cup 68 and a cover 70. The housing parts can be pressed from sheet metal or molded from suitable plastics, the material used normally being dictated by the environmental temperature. The outer peripheries 72 and 74 respectively of the two diaphragms 62 and 64 are spaced apart by a spacer ring 76 and are clamped in sealed relationship between portions of the housing 66 and adjacent end surfaces of the spacer ring 76 when housing cover 70 is secured to the cup 68. Cup 68 has a lateral peripheral flange 78 which with the peripheries of the diaphragms and the spacer ring fit into a stepped peripheral construction 80 on the cover 70. The peripheral extremity 82 of cover 70 is bent inwardly, over the cup flange 78 and rigidly secures and sealingly clamps the two diaphragms and spacer in assembly within the housing.

A vacuum connector 84 extends outwardly from the outer periphery of the spacer ring 76 and provides a fluid passageway 86 from the exterior to the interior of the housing into the middle chamber 88 between the two diaphragms.

Shown in FIG. 5, the stepped periphery of cover 70 is notched at 89 to permit assembly of the components.

A second vacuum connector 90, fastened to the wall of cup 68, provides a fluid passageway from the exterior to the interior of the chamber 92 between the cup and diaphragm. (Chamber 92 for convenience will be designated the rear chamber). In the embodiment of FIGS. 1, 2 and 3, the end wall 94 of cup 68 is apertured with an inwardly directed slight extrusion 96 into which the end of connector is fitted and suitably bonded. When both the cup and the connector are made from metal, as is preferable for higher temperature installations, the bonding can be made with silver solder. When cup and connector are made from plastic (lower temperature operating conditions) they can be molded as a unit or joined by suitable plastic bonding agents. Whenever the connection 90 is made through the cup end wall 94, the inward wall extrusions 96 can be tolerated and moreover provides a smooth finished appearance. Alternatively the vacuum connection 90' (FIG. 4) can be located through the sidewall portion of the cup, in which case the pierced wall opening will have its edges 96' extruded outwardly to avoid interference with and damage the rear chamber diaphragm, when it is pulled against the wall of the cup under application of the vacuum.

In any case two connections for vacuum are provided, one to the middle chamber 88 and the other to the rear chamber 92. The chamber 98 (which will be designated as the front chamber for convenience) provided between the diaphragm 64 and cover 70 is open to ambient or atmospheric pressure through a cover opening, e.g., the central opening 100 in the cover end wall 102. The actuator operator rod 104, which is directly connected to front diaphragm 64, projects through the cover opening 100.

The inner peripheries of the two diaphragms 62 and 64 are firmly clamped between two metal support plates or discs made with slightly cupped outer peripheries. Disc plates I06 and 108 are coaxially clamped on the front diaphragm by a centrally located diaphragm by a centrally located rivet 110 and disc plates 112 and 114 are clamped on the rear diaphragm by a centrally located rivet 116. The outer discs 106 and 114 are similar to each other and the respective inner or facing discs 108 and 112 are similar to each other. Rivet 116 merely serves only to clamp the rear discs 112 and 114 on the rear diaphragm whereas the slightly longer front rivet 110 also serves to secure the flat operator rod 104 to the front diaphragm, passing through an aperture in bent end 118 of rod 104, before it is riveted to tightly clamp the rod 104, discs I06 and 108 and diaphragm 64 as a unit. Even though the flat rod 104 is tightly secured by rivet 110 it can be swiveled by exerting a twist in order to vary its disposition to accommodate different installations. When a round rod operator link is used, as in FIGS. 4, 5 and 12, its end is reduced and serves as the fastening member in lieu of rivet 110.

Inasmuch as the inner discs 108 and 112 are similar, a description of one disc 108, FIGS. 10 and 11, will suffice for both. Disc 108 has two integral bent up, apertured ears 120 and 122, the ear apertures being disposed on a diametral center line of the disc as seen in the FIG. 10 plan view and spaced on either side of the central rivet hole 124. Ears 120 and 122 on the two inner discs serve as anchor devices for a collapsible link unit which will be hereinafter described. The cupped outer periphery 126 of disc 108 is representative of all four of the diaphragm discs and in the case of three of the discs as a coil spring seat.

Returning to FIG. 1, the actuator contains two coil compression springs 128 and 130, spring 128 being placed between the the two diaphragms, seated within the peripheries of the inner discs 108 and 112 and spring 130 being placed in the rear chamber with one end seated within the cupped periphery of the disc 114. The end wall 94 of the housing cup 68 has a frustum shape to provide a spring seat for the outer end of rear spring 130.

Spring 128 biases the two diaphragms 62 and 64 apart with sufficient force to enable operation, through the operator rod 104, of the unit being operated, e.g., provides a force sufficient to rotate the valve plug shown in FIGS. 4 and 5. Similarly, spring 130 biases the rear diaphragm 62 way from the rear wall 94 of cup 68 with substantially the same force as provided by spring 128. The spring forces the both for both springs are chosen so the springs will be readily compressed upon application of vacuum to the respective chambers in which they are disposed.

A collapsible link assembly or unit 132, located in the middle chamber 88, is fastened to each diaphragm by means of the support disc anchor ears 120 and 122 shown in FIGS. and 11. In the preferred embodiment, collapsible link unit 132 (see FIGS. 6 and 7) is made from three pieces of steel, two of which are similar bail shaped wire links 134 and 136 and the third piece is a wide sheet metal link 140. The ends of the legs of both wire links 134 and 136 are bent outwardly to provide short pivot stubs 138. The tow wire links 134 and 136 are pivotally secured to each other at their bight of midportion by a small sheet metal, formed link 140. Link 140 has central opposed edge flange portions 142 and 144 wrapped around the bights of the two wire bails to retain them in assembly and at the same time permit free relative pivoting between limits. At each end of the sheet metal retaining link 140, two integral tabs 146 and 148 extend beyond both sides of the bights of the two wire links, and serve as limit abutments of the legs of the two wire links 134 and 136. The tabs 146 and 148 have an intentional curvature which limits the outward pivoting of links 134 and 136 to approximately the 160 disposition shown in FIGS. 1, 2 and 6. The limit stop arrangement prevents pivoting to a full 180 disposition of the link unit 132 and avoids a dead center or over center disposition of the two wire links which could result in a condition where the link assembly would not collapse when the middle chamber is evacuated.

The bent stub ends 138 of the wire links pivotally fit into the apertured anchor ears 120 and 122 in the inner diaphragm discs 108 and 112 as shown in FIGS. 1, 2 and 3. Because of the resilience of the steel wire links, the pivot ends on the legs of each link can be squeezed slightly together and sprung into anchored disposition with associated ears 120 and 122 on the facing diaphragms support discs. This relationship can be visualized by viewing FIGS. 7 and 11 together.

Referring again to FIG. 1, the three piece collapsible link unit 132 fastened between diaphragms 62 and 64, being made from metal, provides a definite limit to the distances which the centers of diaphragms can be spaced apart due to force of the spring 128. The link unit serves as an articulated connection as well as to delimit a fixed distance between the diaphragm attached end of operator rod 104 and the rear diaphragm 67. Collapse of the link unit must be assured to permit the diaphragms to move toward each other, when vacuum is applied to the center chamber 88, at least to the limit permitted by compression of the coil spring 128.

THREE POSITIONS The three positions of the actuator, from which it derives its type designation, are illustrated respectively in FIGS. 1, 2 and 3. Control of application of the vacuum or low-pressure source will be via one or more manual or automatic control valves (not shown) as desired for the installation.

FIGS. 1 represents the first position, the spring biased extended position of the actuator, in which there is no vacuum applied to either of connectors 84 or 90, the lines (not shown) which fasten to such connectors being opened to ambient pressure surrounding the actuator itself. Pressures being equalized on both sides diaphragms, the bias of spring 128 against the support discs of both diaphragms will force them apart to the limit distance permitted by collapsible link unit 132 and at the same time rear spring 130 will force the rear diaphragms via its support discs toward the cover end of the housing. This combined spring force results in the front diaphragm disc 106 moving to abut the cover end wall 102, at which limit, the attached operator rod 104 is moved out to its fully extended position. The force exerted by the springs to urge the operator rod 104 to its extended position will be selected as desired for a particular installation. One installation in which the actuator will actually be used requires at least a 3.5 pound force to be exerted in urging the actuator rod to extended position, hence the spring compression force of each spring would be at least 3.5 pounds. While it is preferred that the actuator be a complete bidirectional motor with self contained springs for 'urging the actuator operating rod in the one direction, the springs could be omitted from inside of the actuator housing, in which event the component being operated could be spring loaded to pull the operator rod 104 to the extended limit position shown in FIG. 1, and vacuum operation of the actuator would work on opposition to the ex ternal spring.

FIG. 2 illustrates the No. 2 or intermediate actuator position wherein a source of vacuum has been connected to the rear chamber 92 via connector permitting differential pressure across the rear diaphragm 62 to force diaphragm 62 toward the rear wall 94 of the cup to its position as limited by compression of the coil spring 130. This movement of diaphragm 62 is transmitted through its support discs 112 and 114 and the collapsible link unit 132 (which will now be fully extended) to pull the front diaphragm 64, through its support discs, toward the rear wall 94 and thereby retract the operator rod 104 to its intermediate position. The vacuum source must provide a pressure differential, relative to ambient pressure, which when applied to the effective pressure area of the diaphragm 62 will exert enough force to overcome the bias of spring and still provide the requisite specified pulling force on the actuator rod 104. FIG. 2 also clearly illustrates that the wall of diaphragm 62 conforms closely against the inside surface of the cup 68 as it moves toward the rear wall 94. While this is normal in such diaphragm motors, and causes no problem, the situation is different and there can be a problem in connection with the movement of the front diaphragm 64 as will be described in the next portion pertaining to the NO. 3position.

To shift the No. 3 position shown in FIG. 3, the vacuum source is applied to both the rear chamber 92 and the middle chamber 88, via respective connectors 90 and 84. Applying or continuing the connection of vacuum to connector 90 evacuates the rear chamber 92 placing the rear diaphragm 62 in the condition previously described for position No. 2. Evacuation of the middle chamber 88 through the connection 84 and passageway 86 in spacer ring 76 causes a pressure differential across the front diaphragm 64 to move it from the cover toward the rear diaphragm 62, compressing the coil spring 128 to its compact limit condition as shown in FIG. 3. As the diaphragm 64 moves closer to diaphragm 62, its supports discs 106 and 108 force the link unit 132 to collapse to its folded condition and at the same time retract the operator rod 104 into the housing 66 to its maximum retract position No. 3. It should be apparent that the precise location of the No. 3 position can be changed by using a different number of coils in either or both of springs 128 and 130 and that the precise location of the No. 2 position can be changed by using a different number of coils in spring 130 or by changing the length of the legs on the wire form links in the link unit 132.

The previously mentioned problem which can be encountered in connection with front diaphragm 64 is occasioned by the fact that as the diaphragm moves toward the rear with middle chamber 88 connected to a vacuum source, the diaphragm wall rolls across and attempts to conform to the surface of the inner periphery of the spacer ring 76 and as its movement progresses it progressively moves into tight conformity with the front surface of the rear diaphragm 62 which will be flat against the inner side surface of the cup 68. The conformity of the flexible diaphragm wall against the spacer could immediately shut off the passageway 86 and prevent further evacuation of the middle chamber 88. To alleviate blocking of the outlet passage 86, at least the front diaphragm 62 is provided on its rear surface with a series of spaced apart small radial ribs 152 (seen in FIGS. 1, 2 and 9) which will create multiple radial passageways between overlapped surfaces to allow air to be exhausted from the chamber 88 between the two engaged diaphragms.

To further assure that evacuation blocking does not occur, the spacer ring inner periphery is relieved. A preferred manner of relief is to undercut a portion 154 (see FIG. 8) of the inner periphery of spacer ring 76. Such an undercut portion is shown disposed closet to the rear diaphragm 62, although it can be disposed either way, all will intersect the lateral passageway 86. When the front diaphragm 64 in its initial movement rolls over the step 156 formed by the undercut 154, it will not conform to a small annular passageway along the comer of the undercut 154. Since the annular corner passage connects with the passageway 86, blocking or sealing off of the passageway 86 by the diaphragm 62 is prevented. An alternative expedient is shown in FIG. 12 where an annular groove 158 is provided around the inner periphery of the spacer ring. The undercut or stepped embodiment is preferred as it more readily lends itself to inexpensive molding of the spacer ring from plastics than does the groove embodiment. Also, when steel rings are used, the undercut can be machined more readily than the internal groove.

Shown in the sectioned detail view of FIG. 8, both the upper and lower surfaces of spacer ring 76, at the or peripheral edge of the ring, are provided with annular recesses 162 and 164 which, in clamped assembly, cooperate with an annular bead 166 on the outer periphery of the respective diaphragms. This relationship assures that the diaphragms are not only sealingly clamped but are also effectively gripped at its outer periphery to prevent their peripheries from being pulled out from the clamped assembly. As an additional gripping aspect, an annular rib can be formed in the cooperating surfaces of the cup 68 and cover 70, e.g., the rib 168 in flange 78 of cup 68 is shown in FIG. 8, and such a rib 168 will provide a pressure fit around the periphery of the diaphragm and against the spacer ring radially inward of the diaphragm head 166.

The spacer ring 76 provides a stable rigid clamping structure which can be satisfactorily accomplished with rings and from metal or plastic. Steel spacer rings are desirable where temperature conditions approximate 265 F. or above whereas plastics have been successful and found to be fully acceptable for environmental temperatures up to 220 F. One plastic material found to be very satisfactory by itself and more so when fiber glass filled is CELON, an ethyl cellulose thermoplastic.

The diaphragms can be made form rubber or similar materials as required to withstand conditions for various installations. A highly satisfactory oil and temperature resistant material of the diaphragms in actuators used in the automotive field has been found to be a synthetic made from ethylene propylene by Vemay Laboratories, Inc., Yellow Springs, Ohio. It is known to the trade as EPT rubber.

ADDITIONAL COLLAPSIBLE LINK ASSEMBLIES Different structural embodiments of collapsible link units coupled between the two diaphragms in the three position actuator of the present invention are shown in FIGS. 12-27. Some of the collapsible link units are made from nonmetallic materials and represent initial stages in the developments which culminated in the preferred embodiment of the three piece steel link unit, hereinbefore described.

FIG. 12, along with FIGS. 13 and 14 illustrate an embodiment of the three-position actuator which utilizes a rubber X- shaped collapsible link unit 172. The unit 172 is molded from a rubber material with minimum stretch characteristics. The molded end tabs 174 on the legs of unit 172 are clamped under bent over integral punched tabs 176 in the opposed diaphragm support discs.

FIGS. 15 and 16 illustrate a pair of what, for convenience, will be termed diamond links 180 and 182 which, like the X- links 172, are molded from rubber. In this embodiment of collapsible link assembly, auxiliary double hook plates 184 and 186 are secured respectively against each of the opposing diaphragms support discs by the support disc rivet connection and the ends of the diamond links and 182 are looped and firmly fastened under the hooked ends of plates 184 and 186, as shown in FIG. 15.

FIGS. 17 and 18 illustrate the use of a wide rubber band as the collapsible link. The band 190 is pierced by apertures 192 and 194 at diametrically opposite locations. The rivet members of the two diaphragms are used to secure the band 190 between the diaphragms, the rivets passing through the respective rubber bands apertures 192 and 194 and respective small clamping plates 196 and 198 before being riveted to securely clamp the plate 196 or 198, the band 190, the diaphragm and its discs together. The edges of the clamping plates 196 and 198 are bent up as at 199 and have a smooth finish to prevent damage to the rubber band 190. Instead of being sent at 199, the edges of the small clamp plates may be chamfered.

While all of the X-shaped link unit 172, the diamondshaped link units 180 and 182 and the rubber link unit 190 exhibit some stretch characteristics and are not intended to be used under extremes of load and temperature conditions they are satisfactory to provide a collapsible connection having a determined maximum spacing within certain tolerances between the two diaphragms to accomplish the three position operating function of the actuator under some conditions.

FIGS. 19-23 represent several nonmetallic collapsible embodiments which exhibit ability to withstand more extreme conditions of temperature and force than do the other rubber link units 172, 180 and 190, although again these embodiments, using presently known materials, will not be used under extremes of temperature conditions which many automotive components are subjected.

FIG. 19 illustrates a collapsible link unit in which a single rubber O-ring 210 is hooked in a bungee arrangement over double hook plates 212 and 214 secured by riveting against the opposed diaphragm support discs in a manner similar to the hook plates in FIG. 15, although the hook plates will be arranged transverse to each to readily accommodate the looped arrangement of the O-ring. To enable this embodiment of collapsible link unit to be used in actuators operating under somewhat grater load forces without stretching and exceeding the desired maximum spacing limit between diaphragms, the rubber O-ring may be reinforced with a fabric material, along the inner or outer periphery of O-ring 210' as shown at 216 in FIG. 21 or as a central core 218 of O-ring 210" as shown in FIG. 22.

A further embodiment of which exhibits characteristics similar to the O-rings is a flat polypropolene ring 220 shown in FIG. 23. This ring is installed as a collapsible link unit in the same manner as hereinbefore in connection for O-ring 210.

A further embodiment of the collapsible link which exhibits satisfactory and acceptable characteristics under all specified extremes of automotive operating conditions is the metal torsion link embodiment illustrated in FIGS. 24-27. While substantially more expensive than the three piece steel link unit 132, the torsion link unit 230 is considered to have substantially the same reliability and will provide a predetermined maximum spacing distance between diaphragm support discs within the very close tolerances provided by the three piece steel link unit 132.

The torsion spring link unit 230 consists of two dissimilar small coiled torsion spring 232 and 234 with associated steel wire anchors 236 and 238. SPrings 232 and 234. as seen in FIGS. 26 and 27, are coiled in opposite directions and in the relaxed spring condition have their two terminal legs 240, 242 and 244, 246 extending in opposite directions from the ends of the respective coils and disposed essentially in the same plane. The ends 241 and 243 of respective legs of coil spring 232 are made into loops which bend inwardly toward each other (FIG. 26) whereas the loop ends 245 and 247 of respective legs 244 and 246 of coil spring 234 coil in the same direction as does their coiled spring which makes them essentially perpendicular to the plane of their legs (FIG. 27). Such dissimilarity will better accommodate coupling of the two springs. FIG. 25 illustrates the manner in which the two springs units 232 and 234 are fastened together loops 241 and 245 being linked together and loops 243 and 247 being linked together and all leg loops being bent sufiiciently to prevent separation. FIG. 25 also illustrates the appearance of the torsion spring link unit in its collapsed condition.

With the two springs of the torsion spring link unit 230 assembled as shown in FIG. 25, it will be connected, within the diaphragm biasing spring 128', to the opposed diaphragm support discs 250 and 252. Each diaphragm 62 and 64 with its two support discs having been previously riveted in assembly. The outer discs and the operator rod and its connection are all similar to the assembly described in conjunction with FIG. 1. The inner anchor discs 250 and 252 (ones which oppose each other in the assembled double diaphragm) are similar. One such disc 250 is shown in FIG. 28 and has its anchor portions made by piercing and deforming two diametrally located strips of the disc metal upward to form upstanding anchor loops 254 and 256 spaced a sufficient distance apart to accommodate the coiled portion of one of springs 232 and 234 between them. In FIG. 24, one spring 232 is anchored between strip loops 254 and 256 of the disc 250 by slipping the short length of steel wire anchor 236 under one loop, through the spring coil and then under the other loop. The extremities of the wire anchor 236 are then bent over close to the loops to prevent its dislodgement and to prevent engagement with the damage to the diaphragms. The other spring 234 is anchored to disc 252 by its anchor wire 238 in a manner similar to that just described.

This embodiment of anchor disc 250 constitutes one way of providing anchor components in the opposing diaphragm support plates and can be used as an alternative to the punched out and bent up apertured ears 120 and 122 of the hereinbefore described anchor disc 108 shown in FIGS. and 11. An important advantage of the construction of anchor disc 250 is that, using mass production techniques, the slightly less expense per unit will result in substantial savings.

Because of the manner in which the two springs of the torsion spring collapsible link unit 230 are interconnected, their normal torsion bias will be toward the collapsed condition seen in FIG. 25. The torsion bias force of the two springs 232 and 234 in substantially less than the force of compression coil spring 128 located between the two diaphragms which shifts the coil portions of torsion springs to the disposition shown in FIG. 23 where each of the interconnected pairs of legs have an angular disposition approximately like that of the open wire form link 132 seen in FIG. 2. In the opened link condition, the torsion spring legs, being biased toward their collapsed planar condition, can never reach a dead center condition and moreover will always move immediately toward collapsed condition under the torsion bias when a vacuum source is applied to the middle chamber, between the diaphragms.

Although the hereinbefore described internal springs 12 and 130 are straight coil springs, they could be cone-shaped springs. The advantage of the straight spring is that the rate of change of power of the spring is considerably less with a straight spring than with a cone spring. Thus the advantage accruing to the actuator by use of the straight coil springs is a nearer uniform power with a given amount of vacuum at both ends of the travel.

The disadvantage of the straight spring as against the coneshape spring is that in closed position a cone-shape spring is the thickness of the wire diameter while the straight spring in its closed position is considerably longer as is shown in FIG. 3. This feature of a cone spring will permit a shorter cup or housing. The straight spring provides better performance whereas a cone-shape permits use of a smaller housing.

The basic three-position actuator can be used without using either of the internal springs 128 and 130 or an external spring (as was described hereinbefore). Vacuum can be used in lieu of such internal springs and will avoid loss of the built in spring force which must be overcome by the operating vacuum. In such an embodiment, the round rod arm such as rod 42 is used with a shiftable seal arrangement provided between the front chamber wall and the round rod arm, and a vacuum connector is attached to the wall of the front chamber similar to connector as described for the rear chamber. Operating vacuum is then selectively applied to the front chamber as well as to the rear and middle chambers to case actuator shift from and to all three positions.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to the con sidered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

l. A dual diaphragm, multiposition vacuum actuator comprising: housing means securing said diaphragms to provide at least two vacuum operating chambers; means providing fluid communication through said housing into each of said two chambers from the exterior of said housing; a motion transmitting means secured to one of said diaphragms exterior of said two chambers and projecting exterior of said housing; means coacting with said diaphragms urging them in a direction causing maximum extension of said motion transmitting means from said housing including a collapsible device located between and connected to both of said diaphragms enabling said diaphragms to move relatively toward and away from each other between a substantially fixed maximum distance at least when one of said chambers is selectively subjected to vacuum and closely adjacent disposition of said two diaphragms at the end of said housing means opposite the motion transmitting means when both of said chambers are subjected to vacuum.

2. An expansible chamber motor actuator comprising: a housing, two spaced apart movable wall means disposed within said housing dividing the interior of said housing into three chambers; means providing independent fluid communication into each of said three chambers from the exterior of said housing; said movable wall means cooperating with said housing to provide fiuidtight isolation between said three chambers; a power transfer link means secured to one of said wall means and projecting from the interior of one end chamber to the exterior of said housing and shiftable in a path generally aligned with the path of movement of said wall means; a collapsible device located in the center of said three chambers and connected to both of said movable wall means enabling said movable wall means to move relatively away from and toward each other between a substantially fixed maximum distance between said wall means and a closely adjacent disposition.

3, An actuator as defined in claim 2, wherein biasing means coact with the interconnected assembly of said wall means, said collapsible device and said power transfer link means urging said wall means in a direction causing maximum extension of said link means out from said housing, and said interconnected assembly providing means enabling, during actuator operation, variations in alignment of said transfer link means relative to the path of movement of said wall means.

4. An actuator as defined in claim 3, wherein said biasing means comprise resilient means in two of said chambers coacting with respective said wall means.

5. An actuator as claimed in claim 4, wherein said link means in connected to the wall means in a first one of said chambers, said first chamber having an opening an opening to atmospheric pressure; and said resilient means are expansion coil springs disposed in each of the other chambers which together urge said movable walls toward a minimum volume of condition of said first chamber.

5. An actuator as defined in claim 2, wherein said movable wall means are diaphragm, said housing is made in at least parts with means clamping said two parts together at a mid portion; and a spacer ring is provided between said two parts with the outer peripheries of said diaphragms clamping internally of and between end faces of said spacer ring and adjacent associated parts of said housing.

7. An actuator as defined in claim 6, wherein the means which provides fluid communication to the center one of said three chambers comprises a portion of said spacer ring and includes a fluid passageway extending from exterior of said housing through said housing and through said spacer ring to said center chamber.

8. An actuator as defined in claim 7 wherein the inner periphery of said spacer ring includes a peripheral recess intersecting said passageway.

9. An actuator as defined in claim 8 wherein said diaphragm separating said first and the second of said chambers has radially directed ridges means on its second chamber surface 10. An actuator as defined in claim 9, wherein said internal peripheral recess comprises a stepped annular relief of greater diameter than the inner spacer ring periphery.

11. An actuating as defined in claim 9, wherein said peripheral recess is an annular groove.

12. An actuator as defined in claim 6, including diaphragm support plate means secured to each of said diaphragms, and wherein said link means is centrally fastened on the first chamber side of the support plate means on said first diaphragm.

13. An actuator as defined in claim 12, wherein said support plate means on each diaphragm includes a support plate in said second chamber in facing relationship and including anchor means securing opposite portions of said collapsible device.

14 An actuator as defined in claim 12 wherein coiled compression springs are disposed in said second chamber and said third chamber and urge both diaphragms toward a minimum volume condition of said first chamber, and said support plate means include support plates in at least said second chamber with outer peripheral edges of said support plates upturned to form seats for said coiled compression spring located in said second chamber.

15. An actuator as defined in claim 13, wherein said collapsible device incorporates means positively preventing a noncollapsible condition of said collapsible device when disposed in its extended condition.

16. An actuator as defined in claim 15, wherein said collapsible device is made from metal material.

17. An actuator as defined in claim 16, wherein said collapsible device comprises two U-shaped bails and a connecting bracket hinging the center portions of said U-shaped bails and having portions cooperating with said U-shaped bails limiting extension of said U-shaped bails to less than a 180 condition.

18. An actuator as claimed in claim 17, wherein said anchor means on said facing support plates comprise upstanding apertured lugs and the end arms of each of said U-shaped bails have laterally extending journal portions adapted to be sprung into pivotal anchored relationship in association sets of said lugs.

19 An actuator as defined in claim 16, wherein said collapsible device comprises: two coiled torsion spring units, the coils of which are wound in opposite directions and the ends of which form extended arms with loops at the terminal portions thereof; an elongate anchor means is disposed through one of said coiled torsion springs and secures said spring in said anchor means of one of said facing support plates; a second elongate anchor means is disposed through the other of said coiled torsion springs and secures said other torsion spring in said anchor means of the other of said facing support plates; said loops on cooperating ends of said torsion springs being interlinked whereby the torsional bias of said two said coiled torsion springs tends to pull said two diaphragms toward each other; and a compression coil spring disposed between and urging said two diaphragms apart and having a predetermined biasing force substantially stronger than the bias of the said torsion springs extending to urge the two diaphragms toward each other.

20. An actuator as defined in claim 7, wherein said spacer ring is molded from a high impact plastic material.

21, An actuator as defined in claim 20, wherein said plastic spacer ring includes fiber glass filler.

22. An actuator as defined in claim 21, wherein the plastic material is an ethyl cellulose thermoplastic.

23. A actuator as defined in claim 7, wherein said spacer ring is steel.

24. An actuator as defined in claim 2, wherein said collapsible device incorporates means positively preventing a noncollapsible condition of said collapsible device when disposed in its extended condition.

25. An actuator as defined in claim 24, wherein said collapsible device is made form metal material.

26. An actuator as defined in claim 25, wherein said collapsible device comprises two U-shaped bails and a connecting bracket hinging the center portions of said U-shaped bails and having portions cooperating with said U-shaped limiting extension of said U-shaped bails to less than a condition 27. An actuator as claimed in claim 26, wherein anchor means on facing sides of said two wall means comprise diametral spaced socket means and the end arms of each of said U-shaped bails and have laterally extending journal portions adapted to be sprung into pivotal anchored relationship in associated sets of said spaced socket means.

28. An actuator as defined in claim 25, wherein a compression coiled spring is between and urges said two diaphragms apart; said collapsible device comprises two coiled torsion spring units, the coils of which are wound in opposite directions and the ends of which form extended ares with loops at the terminal portions thereof, a pivot anchor rod through one of said coiled torsion springs secures said spring on one of said wall means and a second pivot anchor rod secures the other of said coiled torsion springs on the other so said wall means, said loops on cooperating ends of said torsion springs being interlinked whereby the torsional bias of said two torsion springs tend to pull said two wall means toward each other, and said torsional bias being of a predetermined force weaker than the bias of the said compression coiled spring tending to urge the two wall means away from each other.

29. An actuator as defined in claim 24, wherein said collapsible device is a nonmetallic ring and hook means comprise anchor means on each of said wall means for securing said ring in an undulated interconnection between said two wall means.

30. An actuator as defined in claim 29, wherein said ring is a rubber O-ring.

31. An actuator as defined in claim 30, wherein a fiber material is molded integral with an supports said O-ring.

32. An actuator as defined in claim 29, wherein said ring is flat and made from flexible polypropolene.

33. An actuator as defined in claim 24, wherein said collapsible device comprises two parallel ring shaped links made from nonmetallic material.

34. An actuator as defined in claim 24 wherein said collapsible device comprises a nonmetallic X-shaped link having anchoring end lugs on its arms.

35. A multiposition chamber vacuum actuator comprising a housing, at least two internal diaphragms movable from a spaced apart position to a closely juxtaposed face to face relationship during actuator operation, each of said diaphragms including outer, immovable peripheral edges, a spacer ring cooperating with said diaphragm outer immovable edges to clamp said diaphragms in assembly with said housing, said spacer ring including lateral, outwardly extending fluid communication passage means providing a passage from radially outwardly of the ring to an opening at its inner periphery, and an annular recess around its inner periphery intersecting said passage, and means defining a plurality of radial ribs between diaphragm opposed surfaces each said rib having a cross section height dimension no greaterthan the thickness of said diaphragm, for preventing sealing, fluidtight engagement of opposed surfaces of said diaphragms in said engagement of opposed surfaces of said diaphragms in said diaphragm face to face relationship.

36. A spacer ring as defined in claim 41, molded from at least a high impact plastic material.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,613, 513 D ted October 19 1971 Inventor(s) Jesse Johnson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1,

line 67, after "actuator" insert -wherein the actuator--.

Col. 2, line 10, change "detained" to --detailed--.

, line 29, change "an" to --in--.

, line 31, after "Fig. 4" insert --and--.

, line 56, after "detail" insert --views-.

line 59, change "11" to --22--. line 66, change "or" to --of-. line 21, after "5" insert -is-. line 26, change "level" to -lever--; change "be" to --by. line 29, after "its" insert other--. Col. 4, line 21, after "damage" insert --to--.

, line 37, after "located" delete "diaphragm by a centrally located". line 63, after "discs" insert --serve-. line 66, delete "the" (second occurrence) Col. 3

, line 70, change "outer" to --other--. I

Col. 5 line 3, change "way" to --away-.

, line 5, after "forces" delete "the both".

, line 17, change "tow" to --two--.'

, line 44, change "distances" to --distance--.

, line 61, change "FIGS." to --FIG.-.

line 66, after "sides" insert --of both--. Col. 6, line 38, change "3position" to --3 position--.

, line 50, change "supports" to --support-.

, line 69, after "spacer" insert --surface--.

, line 9, change "closet" to --closest--.

, line 10, change "all" to --and--.

, line 25, change "or" to --outer-.

, line 39, change "and" to -made-.

Col. 7

' Page 1 HM POJUHU H0119) USCOMM-Df 503754359 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 316130513 D d October 19, 1971 Jesse R. Johnson Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 7, line 45, change "CELON" to -CELCON-.

line 50, change "of" to --for-.- line 73, change "links" to --link. line 18, change "sent" to --bent--. line 21, after "rubber" insert -band--. line 33, after "conditions" insert --to. line 49, after "embodiment" delete "of". line 64, change "spring" to -springs-. line 65, change "SPrings to --Springs-. line 4, change "springs" to -spring--. line 29, change "the" to --and--. line 45, change "in" to --is--. -line 51, after "biased" insert --back--. line 56, change "12" to --l28--.

line 9, change "case" to --cause--. line 13, change "the" to --be--. line 35, after "closely" insert -spaced--. line 50, after "center insert --one--. line 56, change "3, to --3.-. line 69, delete "an opening" (second occurrence) Col.

Col.

Col.

line 73, delete "of" (first occurrence). line' 1, change "5" to --6--.

line 2, change "diaphragm" to -diaphragms-. line 2, insert --twoafter "least".

line 5, change "clamping" to -clamped-.

line 19, after "surface" insert (a period). line 23, change "actuating" to -actuator--.

line 35, change "12" to --l3--.

line 58, change "association" to associated--. line 3, change "extending" to --tending-. line 11, change "A" to --An--.

line 22, after "U-shaped" insert -bai1s--.

Col.

Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No. 3 I 613 I Dated October 19, 1971 Jesse R. Johnson Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 12, line 53, change "an" to -and--. Col. 13, lines 4 & 5, delete "in said engagement of opposed surfaces of said diaphragms". line 7, change "41" to ----35--. Col. 14, line 5, change "i" to --in--; change "41" to --35-.

Signed and sealed this 27th day of June 1 972 (SEAL) Attest:

EDWARD M .FLL'J'IUHELR, JR ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents Page 3 ORM (L593 USCOMM-DC 60376-P69 R U 5 GOVERNHENY PRINY'NG OFFCE 969 O355-334 

1. A dual diaphragm, multiposition vacuum actuator comprising: housing means securing said diaphragms to provide at least two vacuum operating chambers; means providing fluid communication through said housing into each of said two chambers from the exterior of said housing; a motion transmitting means secured to one of said diaphragms exterior of said two chambers and projecting exterior of said housing; means coacting with said diaphragms urging them in a direction causing maximum extension of said motion transmitting means from said housing including a collapsible device located between and connected to both of said diaphragms enabling said diaphragms to move relatively toward and away from each other between a substantially fixed maximum distance at least when one of said chambers is selectively subjected to vacuum and closely adjacent disposition of said two diaphragms at the end of said housing means opposite the motion transmitting means when both of said chambers are subjected to vacuum.
 2. An expansible chamber motor actuator comprising: a housing, two spaced apart movable wall means disposed within said housing dividing the interior of said housing into three chambers; means providing independent fluid communication into each of said three chambers from the exterior of said housing; said movable wall means cooperating with said housing to provide fluidtight isolation between said three chambers; a power transfer link means secured to one of said wall means and projecting from the interior of one end chamber to the exterior of said housing and shiftable in a path generally aligned with the path of movement of said wall means; a collapsible device located in the center of said three chambers and connected to both of said movable wall means enabling said movable wall means to move relatively away from and toward each other between a substantially fixed maximum distance between said wall means and a closely adjacent disposition. 3, An actuator as defined in claim 2, wherein biasing means coact with the interconnected assembly of said wall means, said collapsible device and said power transfer link means urging said wall means in a direction causing maximum extension of said link means out from said housing, and said interconnected assembly providing means enabling, during actuator operation, variations in alignment of said transfer link means relative to the path of movement of said wall means.
 4. An actuator as defined in claim 3, wherein said biasing means comprise resilient means in two of said chambers coacting with respective said wall means.
 5. An actuator as claimed in claim 4, wherein said link means in connected to the wall means in a first one of said chambers, said first chamber having an opening an opening to atmospheric pressure; and said resilient means are expansion coil springs disposed in each of the other chambers which together urge said movable walls toward a minimum volume of condition of said first chamber.
 5. An actuator as defined in claim 2, wherein said movable wall means are diaphragm, said housing is made in at least parts with means clamping said two parts together at a mid portion; and a spacer ring is provided between said two parts with the outer peripheries of said diaphRagms clamping internally of and between end faces of said spacer ring and adjacent associated parts of said housing.
 7. An actuator as defined in claim 6, wherein the means which provides fluid communication to the center one of said three chambers comprises a portion of said spacer ring and includes a fluid passageway extending from exterior of said housing through said housing and through said spacer ring to said center chamber.
 8. An actuator as defined in claim 7 wherein the inner periphery of said spacer ring includes a peripheral recess intersecting said passageway.
 9. An actuator as defined in claim 8 wherein said diaphragm separating said first and the second of said chambers has radially directed ridges means on its second chamber surface
 10. An actuator as defined in claim 9, wherein said internal peripheral recess comprises a stepped annular relief of greater diameter than the inner spacer ring periphery.
 11. An actuating as defined in claim 9, wherein said peripheral recess is an annular groove.
 12. An actuator as defined in claim 6, including diaphragm support plate means secured to each of said diaphragms, and wherein said link means is centrally fastened on the first chamber side of the support plate means on said first diaphragm.
 13. An actuator as defined in claim 12, wherein said support plate means on each diaphragm includes a support plate in said second chamber in facing relationship and including anchor means securing opposite portions of said collapsible device. 14 An actuator as defined in claim 12 wherein coiled compression springs are disposed in said second chamber and said third chamber and urge both diaphragms toward a minimum volume condition of said first chamber, and said support plate means include support plates in at least said second chamber with outer peripheral edges of said support plates upturned to form seats for said coiled compression spring located in said second chamber.
 15. An actuator as defined in claim 13, wherein said collapsible device incorporates means positively preventing a noncollapsible condition of said collapsible device when disposed in its extended condition.
 16. An actuator as defined in claim 15, wherein said collapsible device is made from metal material.
 17. An actuator as defined in claim 16, wherein said collapsible device comprises two U-shaped bails and a connecting bracket hinging the center portions of said U-shaped bails and having portions cooperating with said U-shaped bails limiting extension of said U-shaped bails to less than a 180* condition.
 18. An actuator as claimed in claim 17, wherein said anchor means on said facing support plates comprise upstanding apertured lugs and the end arms of each of said U-shaped bails have laterally extending journal portions adapted to be sprung into pivotal anchored relationship in association sets of said lugs. 19 An actuator as defined in claim 16, wherein said collapsible device comprises: two coiled torsion spring units, the coils of which are wound in opposite directions and the ends of which form extended arms with loops at the terminal portions thereof; an elongate anchor means is disposed through one of said coiled torsion springs and secures said spring in said anchor means of one of said facing support plates; a second elongate anchor means is disposed through the other of said coiled torsion springs and secures said other torsion spring in said anchor means of the other of said facing support plates; said loops on cooperating ends of said torsion springs being interlinked whereby the torsional bias of said two said coiled torsion springs tends to pull said two diaphragms toward each other; and a compression coil spring disposed between and urging said two diaphragms apart and having a predetermined biasing force substantially stronger than the bias of the said torsion springs extending to urge the two diaphragms toward each other.
 20. An actuator as defined in claim 7, wherein said spacer ring is molded from a high impact plastic material. 21, An actuator as defined in claim 20, wherein said plastic spacer ring includes fiber glass filler.
 22. An actuator as defined in claim 21, wherein the plastic material is an ethyl cellulose thermoplastic.
 23. A actuator as defined in claim 7, wherein said spacer ring is steel.
 24. An actuator as defined in claim 2, wherein said collapsible device incorporates means positively preventing a noncollapsible condition of said collapsible device when disposed in its extended condition.
 25. An actuator as defined in claim 24, wherein said collapsible device is made form metal material.
 26. An actuator as defined in claim 25, wherein said collapsible device comprises two U-shaped bails and a connecting bracket hinging the center portions of said U-shaped bails and having portions cooperating with said U-shaped limiting extension of said U-shaped bails to less than a 180* condition
 27. An actuator as claimed in claim 26, wherein anchor means on facing sides of said two wall means comprise diametral spaced socket means and the end arms of each of said U-shaped bails and have laterally extending journal portions adapted to be sprung into pivotal anchored relationship in associated sets of said spaced socket means.
 28. An actuator as defined in claim 25, wherein a compression coiled spring is between and urges said two diaphragms apart; said collapsible device comprises two coiled torsion spring units, the coils of which are wound in opposite directions and the ends of which form extended ares with loops at the terminal portions thereof, a pivot anchor rod through one of said coiled torsion springs secures said spring on one of said wall means and a second pivot anchor rod secures the other of said coiled torsion springs on the other so said wall means, said loops on cooperating ends of said torsion springs being interlinked whereby the torsional bias of said two torsion springs tend to pull said two wall means toward each other, and said torsional bias being of a predetermined force weaker than the bias of the said compression coiled spring tending to urge the two wall means away from each other.
 29. An actuator as defined in claim 24, wherein said collapsible device is a nonmetallic ring and hook means comprise anchor means on each of said wall means for securing said ring in an undulated interconnection between said two wall means.
 30. An actuator as defined in claim 29, wherein said ring is a rubber O-ring.
 31. An actuator as defined in claim 30, wherein a fiber material is molded integral with an supports said O-ring.
 32. An actuator as defined in claim 29, wherein said ring is flat and made from flexible polypropolene.
 33. An actuator as defined in claim 24, wherein said collapsible device comprises two parallel ring shaped links made from nonmetallic material.
 34. An actuator as defined in claim 24 wherein said collapsible device comprises a nonmetallic X-shaped link having anchoring end lugs on its arms.
 35. A multiposition chamber vacuum actuator comprising a housing, at least two internal diaphragms movable from a spaced apart position to a closely juxtaposed face to face relationship during actuator operation, each of said diaphragms including outer, immovable peripheral edges, a spacer ring cooperating with said diaphragm outer immovable edges to clamp said diaphragms in assembly with said housing, said spacer ring including lateral, outwardly extending fluid communication passage means providing a passage from radially outwardly of the ring to an opening at its inner periphery, and an annular recess around its inner periphery intersecting said passage, and means defining a plurality of radial ribs between diaphragm opposed surfaces each said rib having a cross section height dimension no greater than the thickness of said diaphragm, for preventing sealing, fluidtight engagement of opposed surfaces of said diaphragms in said engaGement of opposed surfaces of said diaphragms in said diaphragm face to face relationship.
 36. A spacer ring as defined in claim 41, molded from at least a high impact plastic material.
 37. A spacer ring as defined in claim 36, wherein a fiber glass filler is dispersed within said plastic material.
 38. A spacer ring as defined in claim 37, wherein the plastic material is an ethyl cellulose thermoplastic.
 39. A spacer ring as defined i claim 41 wherein the spacer ring material is steel. 